1. Field of the Invention
The present invention relates to a voltage divider for an integrated circuit, and in particular to a voltage divider for an integrated circuit that does not include the use of resistors.
2. Background of the Invention
Voltage dividers are often used in integrated circuits to supply a voltage different from that of an available power source. Typically, voltage dividers in integrated circuits are designed using resistors. The most commonly utilized type of resistor in voltage dividers formed on a semiconductor substrate is the P+ poly resistor formed from polysilicon.
The use of resistors in voltage dividers has known drawbacks. It is often difficult to form resistors with high resistance when using poly-silicon. Poly-silicon resistors often require a large surface area. As a result, typical resistance values are in the range of 200–300 K Ohms. In addition, when using poly-silicon, the manufacturing process must be altered or require additional processing or masking steps to change the voltage values of the voltage divider. Further, poly-silicon resistors often have high tolerances and high temperature coefficients.
The use of transistors to divide voltage is also known in the art. However, prior art use of transistors typically requires the use of many transistors. In addition, prior art voltage division using transistors has typically failed to yield accurate and predictable results.